ptomain vs putrescine

ptomain and putrescine both are nouns.

Word	Noun	Adjective	Verb	Adverb
ptomain	Yes	No	No	No
putrescine	Yes	No	No	No

As nouns, putrescine is a hyponym of ptomain; that is, putrescine is a word with a more specific, narrower meaning than ptomain:

ptomain: any of various amines (such as putrescine or cadaverine) formed by the action of putrefactive bacteria
putrescine: a colorless crystalline ptomaine with a foul odor that is produced in decaying animal matter

Other hyponyms of ptomain include cadaverine.

ptomain (noun)	putrescine (noun)
any of various amines (such as putrescine or cadaverine) formed by the action of putrefactive bacteria	a colorless crystalline ptomaine with a foul odor that is produced in decaying animal matter